Steam has fundamental problems beyond engine startup time that are just not solvable. Gas engines can quickly switch from low-power to high-power, meaning that you can kick it up quickly to pass another car or maintain speed up a hill.
It's all tradeoffs, but responsiveness matters. And in terms of responsiveness steam < diesel < gas < electric. There's a reason both diesel and gas have long coexisted: sometimes you need more responsiveness, and sometimes more constant power. Steam was just too far from acceptable for high speed responsive output.
That's not the problem. If you have boiler pressure, going to higher power briefly is fast. But you might run out of steam on a long hill if the thermal inertia of the boiler is high and something isn't done to increase the fuel feed.
In locomotives, thermal inertia is so great that fuel input has to be increased in advance of long hills. That's part of the fireman's job. Lack of advance planning can result in a train stuck on an upgrade, with the locomotive unable to generate enough power to get the train started again.[1] (There's some wheel slip, too.)
"Little and Often", a training film for steam locomotive fireman, covers this.[2]
This is the source of the phrase "running out of steam".
This is the full startup procedure for a Stanley Steamer.[3] Shows what all the gauges, levers, valves, and pumps do. Cold startup takes 20 minutes, is very tricky, and if botched the vehicle will be seriously damaged. Nice looking car, though. Pinstriping on the leaf springs!
The stanly was a much earlier tech, perhaps the best car of it's generation. But compare that to the doble, perhaps the high point of steam car technology before that personal motive power route was abandoned.
If you had a larger boiler volume, you could have a far larger reserve of power on demand... however, that would have come with a huge amount of danger. Steam explosions killed far too many people back in that era. Keeping the boilers small was a wise precaution.
Response time would be one of steams solvable problems. There has not been much research on this aspect in the last hundred years, but off the top of my head.
1. Response time is already great, You have a reservoir of instantly available energy in the form of steam pressure ready to go whenever you need it. look up steam engines slipping their wheels, in fact one big problem with steam is that it is much easier to apply too much energy. Same problem with electric. they need a good torque management system to deliver only the power that is needed.
2. The reservoir response time is too long, Probably not a problem, that is the whole point of having a reservoir, but if it is, make it faster, fire tube boilers, more surface area, etc, a solvable problem. Consider the response time of the reservoir of an electric car. it is far worse than any steam engine, yet you say it has a faster response time.
No the real reason we don't use steam cars is that the engines are more expensive than internal combustion engines without all that much benefit.
It's not solvable. Yes, temporary response is a thing. But if I'm driving around town but then go on a freeway then what? Does it always over-produce around town? Or does it take time to build the new head of steam needed for the freeway?
Also consider how complex a thing you are proposing vs a gas and electric simple solution of "more input gives more output now."
That said, as neat as steam cars are, there is a reason internal combustion engines won. Probably because they are smaller, lighter and most importantly cheaper.
"Steam has fundamental problems beyond engine startup time that are just not solvable. Gas engines can quickly switch from low-power to high-power..."
A modern steam-powered vehicle could be based on a steam turbine creating electric power, with a battery and electric traction motor (effectively, a series hybrid). This is how many modern power plants work (coal, gas, nuclear) and would be much more efficient than classic steam engines, by targeting an optimal, constant RPM and torque and providing regenerative braking. It would have plenty of peak power and responsiveness, exceeding gas vehicles and similar to a fully electric vehicle.
But even with the high level of efficiency and performance that this configuration would allow, it's likely a non-starter for environmental reasons, unless you can use a much cleaner fuel than coal?
It also seems to me like running pressure vessels around at 70 mph is not going to be a very good idea. There's a variety of possible ways it may not be a good idea; for instance, you can build pressure vessels than can generally stand up to an impact even at that speed, but they will be quite heavy which causes efficiency problems no matter what other advantages may exist, and will be difficult to hit all our other collision safety metrics with. Keep it light enough to avoid that and now they burst on collision. Plus, you know, people drive cars for a long time and don't maintain them, and again, while you can generally engineer them not to explode any amount of sudden steam escape can become a problem in a lot of circumstances... even radiators, much much smaller by volume, have historically become dangerous at failure points due to the heat and pressure involved. I don't think there's a "sweet spot" for any of these concerns, only points in the middle where you end up with all the problems at once.
In reality we as a species are actually pretty good at handling risk. Look at gasoline cars those infernal firebombs on wheels ended up being ubiquitous.
Yeah, we are pretty good at handling risks... as evidenced by our decision to not put steam engines in all our cars.
Engineering solutions have to exist; we can not just will them into being. See also "why our electric cars have not improved in battery density by a factor of magnitude in the past 10 years".
Comments
Steam has fundamental problems beyond engine startup time that are just not solvable. Gas engines can quickly switch from low-power to high-power, meaning that you can kick it up quickly to pass another car or maintain speed up a hill.
It's all tradeoffs, but responsiveness matters. And in terms of responsiveness steam < diesel < gas < electric. There's a reason both diesel and gas have long coexisted: sometimes you need more responsiveness, and sometimes more constant power. Steam was just too far from acceptable for high speed responsive output.
That's not the problem. If you have boiler pressure, going to higher power briefly is fast. But you might run out of steam on a long hill if the thermal inertia of the boiler is high and something isn't done to increase the fuel feed. In locomotives, thermal inertia is so great that fuel input has to be increased in advance of long hills. That's part of the fireman's job. Lack of advance planning can result in a train stuck on an upgrade, with the locomotive unable to generate enough power to get the train started again.[1] (There's some wheel slip, too.)
"Little and Often", a training film for steam locomotive fireman, covers this.[2]
This is the source of the phrase "running out of steam".
This is the full startup procedure for a Stanley Steamer.[3] Shows what all the gauges, levers, valves, and pumps do. Cold startup takes 20 minutes, is very tricky, and if botched the vehicle will be seriously damaged. Nice looking car, though. Pinstriping on the leaf springs!
[1] https://www.youtube.com/watch?v=dJlXB965SAQ
[2] https://www.youtube.com/watch?v=PVIr66K_rUA
[3] https://www.youtube.com/watch?v=Hv1VH07e608
The stanly was a much earlier tech, perhaps the best car of it's generation. But compare that to the doble, perhaps the high point of steam car technology before that personal motive power route was abandoned.
https://youtube.com/v/rUg_ukBwsyo?t=1012
Now admittedly the doble was a high end luxury item, But you can see how it could be possible to have a every mans steam car.
If you had a larger boiler volume, you could have a far larger reserve of power on demand... however, that would have come with a huge amount of danger. Steam explosions killed far too many people back in that era. Keeping the boilers small was a wise precaution.
Response time would be one of steams solvable problems. There has not been much research on this aspect in the last hundred years, but off the top of my head.
1. Response time is already great, You have a reservoir of instantly available energy in the form of steam pressure ready to go whenever you need it. look up steam engines slipping their wheels, in fact one big problem with steam is that it is much easier to apply too much energy. Same problem with electric. they need a good torque management system to deliver only the power that is needed.
2. The reservoir response time is too long, Probably not a problem, that is the whole point of having a reservoir, but if it is, make it faster, fire tube boilers, more surface area, etc, a solvable problem. Consider the response time of the reservoir of an electric car. it is far worse than any steam engine, yet you say it has a faster response time.
No the real reason we don't use steam cars is that the engines are more expensive than internal combustion engines without all that much benefit.
It's not solvable. Yes, temporary response is a thing. But if I'm driving around town but then go on a freeway then what? Does it always over-produce around town? Or does it take time to build the new head of steam needed for the freeway?
Also consider how complex a thing you are proposing vs a gas and electric simple solution of "more input gives more output now."
Here is how they solved it in 1925. I feel with our many modern advancements we could do much better.
https://youtube.com/v/rUg_ukBwsyo?t=1012
That said, as neat as steam cars are, there is a reason internal combustion engines won. Probably because they are smaller, lighter and most importantly cheaper.
A modern steam-powered vehicle could be based on a steam turbine creating electric power, with a battery and electric traction motor (effectively, a series hybrid). This is how many modern power plants work (coal, gas, nuclear) and would be much more efficient than classic steam engines, by targeting an optimal, constant RPM and torque and providing regenerative braking. It would have plenty of peak power and responsiveness, exceeding gas vehicles and similar to a fully electric vehicle.
But even with the high level of efficiency and performance that this configuration would allow, it's likely a non-starter for environmental reasons, unless you can use a much cleaner fuel than coal?
It also seems to me like running pressure vessels around at 70 mph is not going to be a very good idea. There's a variety of possible ways it may not be a good idea; for instance, you can build pressure vessels than can generally stand up to an impact even at that speed, but they will be quite heavy which causes efficiency problems no matter what other advantages may exist, and will be difficult to hit all our other collision safety metrics with. Keep it light enough to avoid that and now they burst on collision. Plus, you know, people drive cars for a long time and don't maintain them, and again, while you can generally engineer them not to explode any amount of sudden steam escape can become a problem in a lot of circumstances... even radiators, much much smaller by volume, have historically become dangerous at failure points due to the heat and pressure involved. I don't think there's a "sweet spot" for any of these concerns, only points in the middle where you end up with all the problems at once.
As opposed to running a class D metal fire in training at 70mph.
https://www.youtube.com/results?search_query=electric+car+fi...
In reality we as a species are actually pretty good at handling risk. Look at gasoline cars those infernal firebombs on wheels ended up being ubiquitous.
Yeah, we are pretty good at handling risks... as evidenced by our decision to not put steam engines in all our cars.
Engineering solutions have to exist; we can not just will them into being. See also "why our electric cars have not improved in battery density by a factor of magnitude in the past 10 years".
Hydrogen fuel cell vehicles store highly explosive H2 in tanks at up to 700 bar / 10,000 psi. That’s at least 20X more pressure than any steam engine!